1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.16 |
static const char RCSid[] = "$Id: srcsamp.c,v 2.15 2008/12/10 17:33:23 greg Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
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* Source sampling routines |
6 |
greg |
2.7 |
* |
7 |
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* External symbols declared in source.h |
8 |
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*/ |
9 |
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10 |
greg |
2.8 |
#include "copyright.h" |
11 |
greg |
1.1 |
|
12 |
greg |
1.4 |
#include "ray.h" |
13 |
greg |
1.1 |
|
14 |
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#include "source.h" |
15 |
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16 |
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#include "random.h" |
17 |
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18 |
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19 |
greg |
2.5 |
static int cyl_partit(), flt_partit(); |
20 |
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21 |
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22 |
greg |
1.1 |
double |
23 |
greg |
1.4 |
nextssamp(r, si) /* compute sample for source, rtn. distance */ |
24 |
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register RAY *r; /* origin is read, direction is set */ |
25 |
greg |
1.1 |
register SRCINDEX *si; /* source index (modified to current) */ |
26 |
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{ |
27 |
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int cent[3], size[3], parr[2]; |
28 |
greg |
2.16 |
SRCREC *srcp; |
29 |
greg |
1.1 |
FVECT vpos; |
30 |
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double d; |
31 |
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register int i; |
32 |
greg |
2.2 |
nextsample: |
33 |
greg |
1.1 |
while (++si->sp >= si->np) { /* get next sample */ |
34 |
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if (++si->sn >= nsources) |
35 |
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return(0.0); /* no more */ |
36 |
greg |
1.7 |
if (source[si->sn].sflags & SSKIP) |
37 |
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si->np = 0; |
38 |
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else if (srcsizerat <= FTINY) |
39 |
greg |
1.4 |
nopart(si, r); |
40 |
greg |
1.1 |
else { |
41 |
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for (i = si->sn; source[i].sflags & SVIRTUAL; |
42 |
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i = source[i].sa.sv.sn) |
43 |
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; /* partition source */ |
44 |
greg |
1.4 |
(*sfun[source[i].so->otype].of->partit)(si, r); |
45 |
greg |
1.1 |
} |
46 |
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si->sp = -1; |
47 |
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} |
48 |
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/* get partition */ |
49 |
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cent[0] = cent[1] = cent[2] = 0; |
50 |
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size[0] = size[1] = size[2] = MAXSPART; |
51 |
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parr[0] = 0; parr[1] = si->sp; |
52 |
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if (!skipparts(cent, size, parr, si->spt)) |
53 |
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error(CONSISTENCY, "bad source partition in nextssamp"); |
54 |
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/* compute sample */ |
55 |
greg |
2.16 |
srcp = source + si->sn; |
56 |
greg |
1.1 |
if (dstrsrc > FTINY) { /* jitter sample */ |
57 |
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dimlist[ndims] = si->sn + 8831; |
58 |
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dimlist[ndims+1] = si->sp + 3109; |
59 |
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d = urand(ilhash(dimlist,ndims+2)+samplendx); |
60 |
greg |
2.16 |
if (srcp->sflags & SFLAT) { |
61 |
greg |
1.1 |
multisamp(vpos, 2, d); |
62 |
greg |
2.12 |
vpos[SW] = 0.5; |
63 |
greg |
1.1 |
} else |
64 |
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multisamp(vpos, 3, d); |
65 |
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for (i = 0; i < 3; i++) |
66 |
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vpos[i] = dstrsrc * (1. - 2.*vpos[i]) * |
67 |
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(double)size[i]/MAXSPART; |
68 |
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} else |
69 |
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vpos[0] = vpos[1] = vpos[2] = 0.0; |
70 |
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71 |
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for (i = 0; i < 3; i++) |
72 |
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vpos[i] += (double)cent[i]/MAXSPART; |
73 |
greg |
2.12 |
/* avoid circular aiming failures */ |
74 |
greg |
2.16 |
if ((srcp->sflags & SCIR) && (si->np > 1 || dstrsrc > 0.7)) { |
75 |
greg |
2.12 |
FVECT trim; |
76 |
greg |
2.16 |
if (srcp->sflags & (SFLAT|SDISTANT)) { |
77 |
greg |
2.12 |
d = 1.12837917; /* correct setflatss() */ |
78 |
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trim[SU] = d*sqrt(1.0 - 0.5*vpos[SV]*vpos[SV]); |
79 |
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trim[SV] = d*sqrt(1.0 - 0.5*vpos[SU]*vpos[SU]); |
80 |
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trim[SW] = 0.0; |
81 |
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} else { |
82 |
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trim[SW] = trim[SU] = vpos[SU]*vpos[SU]; |
83 |
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d = vpos[SV]*vpos[SV]; |
84 |
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if (d > trim[SW]) trim[SW] = d; |
85 |
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trim[SU] += d; |
86 |
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d = vpos[SW]*vpos[SW]; |
87 |
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if (d > trim[SW]) trim[SW] = d; |
88 |
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trim[SU] += d; |
89 |
greg |
2.15 |
if (trim[SU] > FTINY*FTINY) { |
90 |
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d = 1.0/0.7236; /* correct sphsetsrc() */ |
91 |
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trim[SW] = trim[SV] = trim[SU] = |
92 |
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d*sqrt(trim[SW]/trim[SU]); |
93 |
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} else |
94 |
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trim[SW] = trim[SV] = trim[SU] = 0.0; |
95 |
greg |
2.12 |
} |
96 |
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for (i = 0; i < 3; i++) |
97 |
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vpos[i] *= trim[i]; |
98 |
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} |
99 |
greg |
1.1 |
/* compute direction */ |
100 |
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for (i = 0; i < 3; i++) |
101 |
greg |
2.16 |
r->rdir[i] = srcp->sloc[i] + |
102 |
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vpos[SU]*srcp->ss[SU][i] + |
103 |
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vpos[SV]*srcp->ss[SV][i] + |
104 |
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vpos[SW]*srcp->ss[SW][i]; |
105 |
greg |
1.1 |
|
106 |
greg |
2.16 |
if (!(srcp->sflags & SDISTANT)) |
107 |
greg |
1.1 |
for (i = 0; i < 3; i++) |
108 |
greg |
1.4 |
r->rdir[i] -= r->rorg[i]; |
109 |
greg |
1.1 |
/* compute distance */ |
110 |
greg |
1.4 |
if ((d = normalize(r->rdir)) == 0.0) |
111 |
greg |
2.2 |
goto nextsample; /* at source! */ |
112 |
greg |
1.1 |
|
113 |
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/* compute sample size */ |
114 |
greg |
2.16 |
if (srcp->sflags & SFLAT) { |
115 |
greg |
2.6 |
si->dom = sflatform(si->sn, r->rdir); |
116 |
greg |
2.4 |
si->dom *= size[SU]*size[SV]/(MAXSPART*(double)MAXSPART); |
117 |
greg |
2.16 |
} else if (srcp->sflags & SCYL) { |
118 |
greg |
2.6 |
si->dom = scylform(si->sn, r->rdir); |
119 |
greg |
2.4 |
si->dom *= size[SU]/(double)MAXSPART; |
120 |
greg |
1.1 |
} else { |
121 |
greg |
2.6 |
si->dom = size[SU]*size[SV]*(double)size[SW] / |
122 |
greg |
2.4 |
(MAXSPART*MAXSPART*(double)MAXSPART) ; |
123 |
greg |
1.1 |
} |
124 |
greg |
2.16 |
if (srcp->sflags & SDISTANT) { |
125 |
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si->dom *= srcp->ss2; |
126 |
greg |
1.1 |
return(FHUGE); |
127 |
greg |
2.6 |
} |
128 |
greg |
2.3 |
if (si->dom <= 1e-4) |
129 |
greg |
2.2 |
goto nextsample; /* behind source? */ |
130 |
greg |
2.16 |
si->dom *= srcp->ss2/(d*d); |
131 |
greg |
1.1 |
return(d); /* sample OK, return distance */ |
132 |
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} |
133 |
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134 |
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135 |
greg |
2.7 |
int |
136 |
greg |
1.1 |
skipparts(ct, sz, pp, pt) /* skip to requested partition */ |
137 |
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int ct[3], sz[3]; /* center and size of partition (returned) */ |
138 |
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register int pp[2]; /* current index, number to skip (modified) */ |
139 |
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unsigned char *pt; /* partition array */ |
140 |
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{ |
141 |
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register int p; |
142 |
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/* check this partition */ |
143 |
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p = spart(pt, pp[0]); |
144 |
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pp[0]++; |
145 |
schorsch |
2.10 |
if (p == S0) { /* leaf partition */ |
146 |
greg |
1.1 |
if (pp[1]) { |
147 |
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pp[1]--; |
148 |
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return(0); /* not there yet */ |
149 |
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} else |
150 |
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return(1); /* we've arrived */ |
151 |
schorsch |
2.10 |
} |
152 |
greg |
1.1 |
/* else check lower */ |
153 |
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sz[p] >>= 1; |
154 |
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ct[p] -= sz[p]; |
155 |
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if (skipparts(ct, sz, pp, pt)) |
156 |
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return(1); /* return hit */ |
157 |
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/* else check upper */ |
158 |
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ct[p] += sz[p] << 1; |
159 |
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if (skipparts(ct, sz, pp, pt)) |
160 |
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return(1); /* return hit */ |
161 |
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/* else return to starting position */ |
162 |
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ct[p] -= sz[p]; |
163 |
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sz[p] <<= 1; |
164 |
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return(0); /* return miss */ |
165 |
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} |
166 |
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167 |
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168 |
greg |
2.7 |
void |
169 |
greg |
1.4 |
nopart(si, r) /* single source partition */ |
170 |
greg |
1.1 |
register SRCINDEX *si; |
171 |
greg |
1.4 |
RAY *r; |
172 |
greg |
1.1 |
{ |
173 |
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clrpart(si->spt); |
174 |
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setpart(si->spt, 0, S0); |
175 |
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si->np = 1; |
176 |
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} |
177 |
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178 |
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179 |
greg |
2.7 |
void |
180 |
greg |
1.4 |
cylpart(si, r) /* partition a cylinder */ |
181 |
greg |
1.1 |
SRCINDEX *si; |
182 |
greg |
1.4 |
register RAY *r; |
183 |
greg |
1.1 |
{ |
184 |
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double dist2, safedist2, dist2cent, rad2; |
185 |
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FVECT v; |
186 |
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register SRCREC *sp; |
187 |
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int pi; |
188 |
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/* first check point location */ |
189 |
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clrpart(si->spt); |
190 |
greg |
1.4 |
sp = source + si->sn; |
191 |
greg |
1.3 |
rad2 = 1.365 * DOT(sp->ss[SV],sp->ss[SV]); |
192 |
greg |
1.4 |
v[0] = r->rorg[0] - sp->sloc[0]; |
193 |
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v[1] = r->rorg[1] - sp->sloc[1]; |
194 |
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v[2] = r->rorg[2] - sp->sloc[2]; |
195 |
greg |
1.1 |
dist2 = DOT(v,sp->ss[SU]); |
196 |
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safedist2 = DOT(sp->ss[SU],sp->ss[SU]); |
197 |
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dist2 *= dist2 / safedist2; |
198 |
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dist2cent = DOT(v,v); |
199 |
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dist2 = dist2cent - dist2; |
200 |
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if (dist2 <= rad2) { /* point inside extended cylinder */ |
201 |
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si->np = 0; |
202 |
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return; |
203 |
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} |
204 |
greg |
1.4 |
safedist2 *= 4.*r->rweight*r->rweight/(srcsizerat*srcsizerat); |
205 |
greg |
1.5 |
if (dist2 <= 4.*rad2 || /* point too close to subdivide */ |
206 |
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dist2cent >= safedist2) { /* or too far */ |
207 |
greg |
1.1 |
setpart(si->spt, 0, S0); |
208 |
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si->np = 1; |
209 |
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return; |
210 |
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} |
211 |
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pi = 0; |
212 |
greg |
1.4 |
si->np = cyl_partit(r->rorg, si->spt, &pi, MAXSPART, |
213 |
greg |
1.1 |
sp->sloc, sp->ss[SU], safedist2); |
214 |
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} |
215 |
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216 |
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217 |
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static int |
218 |
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cyl_partit(ro, pt, pi, mp, cent, axis, d2) /* slice a cylinder */ |
219 |
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FVECT ro; |
220 |
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unsigned char *pt; |
221 |
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register int *pi; |
222 |
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int mp; |
223 |
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FVECT cent, axis; |
224 |
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double d2; |
225 |
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{ |
226 |
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FVECT newct, newax; |
227 |
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int npl, npu; |
228 |
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229 |
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if (mp < 2 || dist2(ro, cent) >= d2) { /* hit limit? */ |
230 |
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setpart(pt, *pi, S0); |
231 |
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(*pi)++; |
232 |
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return(1); |
233 |
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} |
234 |
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/* subdivide */ |
235 |
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setpart(pt, *pi, SU); |
236 |
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(*pi)++; |
237 |
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newax[0] = .5*axis[0]; |
238 |
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newax[1] = .5*axis[1]; |
239 |
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newax[2] = .5*axis[2]; |
240 |
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d2 *= 0.25; |
241 |
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/* lower half */ |
242 |
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newct[0] = cent[0] - newax[0]; |
243 |
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newct[1] = cent[1] - newax[1]; |
244 |
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newct[2] = cent[2] - newax[2]; |
245 |
greg |
1.2 |
npl = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
246 |
greg |
1.1 |
/* upper half */ |
247 |
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newct[0] = cent[0] + newax[0]; |
248 |
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newct[1] = cent[1] + newax[1]; |
249 |
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newct[2] = cent[2] + newax[2]; |
250 |
greg |
1.2 |
npu = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
251 |
greg |
1.1 |
/* return total */ |
252 |
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return(npl + npu); |
253 |
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} |
254 |
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255 |
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256 |
greg |
2.7 |
void |
257 |
greg |
1.4 |
flatpart(si, r) /* partition a flat source */ |
258 |
greg |
1.1 |
register SRCINDEX *si; |
259 |
greg |
1.5 |
register RAY *r; |
260 |
greg |
1.1 |
{ |
261 |
schorsch |
2.9 |
register RREAL *vp; |
262 |
greg |
1.5 |
FVECT v; |
263 |
greg |
1.1 |
double du2, dv2; |
264 |
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int pi; |
265 |
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266 |
greg |
1.5 |
clrpart(si->spt); |
267 |
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vp = source[si->sn].sloc; |
268 |
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v[0] = r->rorg[0] - vp[0]; |
269 |
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v[1] = r->rorg[1] - vp[1]; |
270 |
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v[2] = r->rorg[2] - vp[2]; |
271 |
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vp = source[si->sn].snorm; |
272 |
greg |
2.11 |
if (DOT(v,vp) <= 0.) { /* behind source */ |
273 |
greg |
1.5 |
si->np = 0; |
274 |
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return; |
275 |
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} |
276 |
greg |
1.4 |
dv2 = 2.*r->rweight/srcsizerat; |
277 |
|
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dv2 *= dv2; |
278 |
greg |
1.1 |
vp = source[si->sn].ss[SU]; |
279 |
greg |
1.4 |
du2 = dv2 * DOT(vp,vp); |
280 |
greg |
1.1 |
vp = source[si->sn].ss[SV]; |
281 |
greg |
1.4 |
dv2 *= DOT(vp,vp); |
282 |
greg |
1.1 |
pi = 0; |
283 |
greg |
1.4 |
si->np = flt_partit(r->rorg, si->spt, &pi, MAXSPART, |
284 |
|
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source[si->sn].sloc, |
285 |
greg |
1.1 |
source[si->sn].ss[SU], source[si->sn].ss[SV], du2, dv2); |
286 |
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} |
287 |
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288 |
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289 |
|
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static int |
290 |
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flt_partit(ro, pt, pi, mp, cent, u, v, du2, dv2) /* partition flatty */ |
291 |
|
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FVECT ro; |
292 |
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unsigned char *pt; |
293 |
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register int *pi; |
294 |
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int mp; |
295 |
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FVECT cent, u, v; |
296 |
|
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double du2, dv2; |
297 |
|
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{ |
298 |
|
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double d2; |
299 |
|
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FVECT newct, newax; |
300 |
|
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int npl, npu; |
301 |
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|
302 |
|
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if (mp < 2 || ((d2 = dist2(ro, cent)) >= du2 |
303 |
|
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&& d2 >= dv2)) { /* hit limit? */ |
304 |
|
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setpart(pt, *pi, S0); |
305 |
|
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(*pi)++; |
306 |
|
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return(1); |
307 |
|
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} |
308 |
|
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if (du2 > dv2) { /* subdivide in U */ |
309 |
|
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setpart(pt, *pi, SU); |
310 |
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(*pi)++; |
311 |
|
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newax[0] = .5*u[0]; |
312 |
|
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newax[1] = .5*u[1]; |
313 |
|
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newax[2] = .5*u[2]; |
314 |
|
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u = newax; |
315 |
|
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du2 *= 0.25; |
316 |
|
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} else { /* subdivide in V */ |
317 |
|
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setpart(pt, *pi, SV); |
318 |
|
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(*pi)++; |
319 |
|
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newax[0] = .5*v[0]; |
320 |
|
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newax[1] = .5*v[1]; |
321 |
|
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newax[2] = .5*v[2]; |
322 |
|
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v = newax; |
323 |
|
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dv2 *= 0.25; |
324 |
|
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} |
325 |
|
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/* lower half */ |
326 |
|
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newct[0] = cent[0] - newax[0]; |
327 |
|
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newct[1] = cent[1] - newax[1]; |
328 |
|
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newct[2] = cent[2] - newax[2]; |
329 |
greg |
1.2 |
npl = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
330 |
greg |
1.1 |
/* upper half */ |
331 |
|
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newct[0] = cent[0] + newax[0]; |
332 |
|
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newct[1] = cent[1] + newax[1]; |
333 |
|
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newct[2] = cent[2] + newax[2]; |
334 |
greg |
1.2 |
npu = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
335 |
greg |
1.1 |
/* return total */ |
336 |
|
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return(npl + npu); |
337 |
|
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} |
338 |
|
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|
339 |
|
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|
340 |
|
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double |
341 |
|
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scylform(sn, dir) /* compute cosine for cylinder's projection */ |
342 |
|
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int sn; |
343 |
|
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register FVECT dir; /* assume normalized */ |
344 |
|
|
{ |
345 |
schorsch |
2.9 |
register RREAL *dv; |
346 |
greg |
1.1 |
double d; |
347 |
|
|
|
348 |
|
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dv = source[sn].ss[SU]; |
349 |
|
|
d = DOT(dir, dv); |
350 |
|
|
d *= d / DOT(dv,dv); |
351 |
|
|
return(sqrt(1. - d)); |
352 |
|
|
} |